A system for generating an output image for display by processing a wide-angle image taken by a camera provided with a wide-angle lens such as a fisheye lens and the like has been proposed. As one of those image processing systems, a system for generating a clip image including a target from the image and displaying/outputting it is known.
As illustrated in FIG. 7, when a predetermined area is to be clipped from a image obtained by using a wide-angle lens such as a fisheye lens, the target is inclined in accordance with a position of the target. Thus, when a clip image is to be generated from the image, rotation processing according to the inclination is generally executed.
However, an orientation of the target in the clip image to be displayed is changed largely and rapidly by an influence of processing for rotating the clip image, and there is a problem that the display image is hard to be seen. This is particularly remarkable when a image obtained by a fisheye lens (see FIG. 7) with which an orientation of a target is inverted with respect to a center of the image is used or when the camera is installed on a ceiling or the like so that an optical axis direction of the lens goes vertically and the target passes in the vicinity immediately under the camera.